STOCK-BASED COMPENSATION - Allocation of Share-based Compensation (Details) - USD ($)
$ in Thousands |
3 Months Ended |
9 Months Ended |
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
$ 1,527
|
$ 4,955
|
$ 5,381
|
$ 8,863
|
| Cost of revenue |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
44
|
200
|
124
|
517
|
| Research and development |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
85
|
374
|
396
|
673
|
| Sales and marketing |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
341
|
1,672
|
1,283
|
3,143
|
| General and administrative |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
1,057
|
2,709
|
3,578
|
4,530
|
| Employees |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
1,519
|
4,907
|
5,367
|
8,638
|
| Non-employees |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
8
|
48
|
14
|
225
|
| Stock options |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
819
|
3,279
|
2,135
|
4,388
|
| Restricted stock |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
346
|
0
|
692
|
0
|
| Restricted stock units (RSUs) |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
262
|
1,590
|
2,261
|
4,259
|
| Employee Stock Purchase Plan |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Allocated stock-based compensation expense |
$ 100
|
$ 86
|
$ 293
|
$ 216
|